Hook gate for sewing machines



Jan. 9, 1968 BONO 3,362,364

HOOK GATE FOR SEWING MACHINES Filed July 27, 1965 2 Shets-Sheet .1

Jams, 1968 LBQNO 3,362,364

7 HOOK GATE FOR SEWING MACHINES Filed July 27, 1965 2 Sheets-Sheet 2 ss s2 s5 s5 no.5

United States Patent ABSTRACT OF THE DISCLOSURE A hook assembly for a sewing machine comprising a hook gate body rotatable about an axis which is inclined relative to the axis along which the needle reciprocates, said hook gate body being adapted to hold a thread bobbin which, in turn, is held therein against rotational movement. The hook assembly is mounted within a portion of the machine housing which includes a cover which is displaceable independently of the bobbin between an open position whereby access to the bobbin is provided and a closed position whereby the cover presses the bobbin axially against the hook gate body.

The present invention is directed to an improved arrangement for a hook assembly in sewing machines and specifically is directed to an arrangement whereby the bobbin as well as the bobbin holder may be assembled with or removed from the hook body regardless of the position of the sewing needle and whereby the hook gate may be opened without the bobbin or bobbin holder falling away from the hook body.

Traditionally, with the hook gate being in open position, either for the purpose of inserting or for removing the bobbin holder from the hook body, the bobbin holder is free to fall from the hook body and the bobbin itself is free to fall from the bobbin holder. Additionally, in prior machines, if the sewing needle were at its bottom dead-center position it would be in position to engage a recess in the bobbin holder and thereby prevent either insertion or removal of the bobbin holder relative to the hook body.

Devices which up to now have been adapted to prevent the falling away of the bobbin holder or to prevent the opening of the hook gate when the sewing needle is at or near lower dead-center position, have nullified a fundamental advantage which was intended for the type of hook gate assembly to which these devices were applied, and that is, their constructional simplicity relative to rotary hooks of the closed-race type.

An object of the present invention is to provide a sewing machine with a hook assembly whereby the bobbin holder remains in place in the hook body although the hook gate is open and wereby the bobbin holder is itself easily removable or insertable in said hook body.

Another object of this invention is to provide a hook assembly whereby removal or insertion of the bobbin holder may be effected without danger of the bobbin falling from the bobbin holder.

Another object of this invention is to provide a hook assembly whereby the bobbin holder may be removed or installed with regard to the hook body regardless of the sewing needle position and without danger of breaking or bending said needle.

Another object of the present invention is to provide a hook assembly wherein the bobbin holder may be installed and properly securely positioned independently of the hook gate being closed so that there is avoided the possibility of dislodging the bobbin holder during the subsequent closing of the gate and consequent damage to the sewing needle or the hook itself.

3,362,364 Patented Jan. 9, 1968 A further object of this invention is to provide a hook arrangement whereby thread fragments or thread detritus which results from friction between the thread and the hook is prevented from falling into the hook driving mechanism.

The above and other objects of this invention will become apparent from a reading of the following detailed description of a preferred embodiment which is referred to the attached drawings, wherein:

FIGURE 1 is a vertical end view through the sewing machine housing and shows the hook assembly as applied to a free arm type sewing machine;

FIGURE 2 is a sectional view taken along line II-II of FIGURE 1;

FIGURE 3 is a view analogous to FIGURE 1 but as applied to a flat base type sewing machine;

FIGURE 4 is a perspective view of the hook assembly with the various parts shown in dis-assembled condition;

FIGURE 5 is a vertical View of the gate cover parts in dis-assembled condition;

FIGURES 6 and 7 are respective detail views of the bobbin holder; and.

FIGURES 8 and 9 are respective detail views of the hook body.

With particular reference to FIGURES 13, the base housing 1 of the sewing machine is closed on its upper surface by needle plate 2 which includes slot 3 for sewing needle 4 to reciprocatingly pass therethrough. Needle 4 is reciprocatingly driven through known means (not shown) in order to form stitches, and in the case of a zig-zag machine the needle is also oscillated perpendicularly to the plane of FIGURE 1.

A fabric feed dog 7 comprises a serrated upper surface portion 6 which is moved in slot 5 through known means 8. Dog 7 passes through slot 9 which is formed in dividin g wall 10 which is a part of housing 1 and which divides the base housing into a separate upper and lower chamber, A and B, respectively. Dividing wall 10 is inclined relative to a horizontal line by angle X which can be in the range of 35 to 55 degrees. In the lower chamber there is rotatably mounted, in parallel relation to wall 10, a shaft 11 which is driven by the sewing machine drive means and which in turn drives the hook by means of bevel gear 12, fixedly mounted on shaft 11, and bevel gear 21, fixedly mounted on shaft 19 by means of screw 20.

A cylindrical body 13 is adjustably mounted in a bored portion 13a which, as is seen in FIGURE 2, is part of the fixed housing 1, said body 13 including a diametral hole 14 running perpendicular to the axis of body 13. Bushing 15 is securely mounted within hole 14 by means of machine screw 16 which is threaded axially through body 13. By loosening screw 16, bushing 15 can be moved axially within hole 14. On the other hand, if it is desired to alter the angular disposition of bushing 15 relative to wall 10, it is necessary to loosen set screw 17 which is threadedly mounted in the fixed bored portion 13a of housing 1 and extends into a circumferential groove 18 in body 13, and then turn body 13 about its axis within bored portion 13a, such turning being done by hand, and then screw 17 is retightened. Body 13 is coaxial relative to shaft 11 and adjacent to the end portion thereof on which is mounted the bevel gear 12. As is evident in FIGURE 2, in operation body 13 is stationary since it is secured to fixed portion 13a by set screw 17 while, however, shaft 11 is free to rotate and thereby drive shaft 19 via bevel gears 12 and 21.

Shaft 19 is rotatably mounted within bushing 15 and extends beyond opening 22 in wall 10 into the upper chamber A where it fixedly mounts hook gate body 23.

Hook gate body 23 (FIGURE 4) comprises an outer circumferential rim 24 whose circumferential continuity is interrupted by a recess which extends radially inwardly from said rim and along a portion of the bottom radial wall 70 of the body 23. The rim end walls 27 and 27' at each end of the recess are downwardly slanted in the same circumferential direction from the upper to the lower opposite axial faces of the rim 24 (the slant of Wall 27 being easily discernible in FIGURE 4 while the slant of end wall 27 is less discernible but still evident from the fact that the side wall 25 of recess 25 is located circumferentially to the right of the top edge of end wall 27). The portion 26 of rim 24 which is circumferentially delimited by end wall 27 constitutes a gripping point which is substantially similar to the gripping point in conventional horizontally mounted hook gate bodies excepting for the fact that the upper edge 27", which is intended to graze past the sewing needle, is radially inwardly inclined (see FIGURE 8) relative to the axis of shaft 19 at an angle thereto substantially equal to angle x whereby edge 27" will be substantially parallel to needle 4 when said gripping point 26 is located adjacent to said needle, which occurs when portion 26 is at the highest point of its circular trajectory relative to the axis of shaft 19.

Gripping point 26 is protected by thread guiding plate 28 which follows the curvature of rim 24 and is secured to said rim to bridge across recess 25 by means of screws 29, one On each side of said recess. The upper edge 36 of plate 28 lies substantially in the same plane as the upper edge of gripping point 26 whereby said plate 28 serves to protect the hands of the machine operator from said point.

From the lower edge 31 of plate 28 extends a tongue 32 bent radially inwardly relative to the curvature of plate 28 and, therefore, relative to the body 23. Tongue 32 is defined by an edge profile 33 which is located beneath and in the vicinity of point 26. During rotation of hook body 23 (profile 33 comes against sewing needle 4 while the needle in moving upwards from its lower dead-center position and the sliding action of profile 33 against the needle prevents the latter from interferring with gripping point 26 (see FIGURES 8 and 9).

The interior of gate body 23 includes a circular race 34 which serves as a support surface for the circular flange 35 of bobbin holder 36. The bobbin holder 36 includes a cylindrical wall 3'7 which is rigid with flange 35 and whose central axis is eccentric relative to the axis of flange 35. As is seen in FIGURE 7, flange 35 is located intermediate the ends of cylindrical wall 37. Wall 37 receives bobbin 38 concentrically therein.

At the point where the flange 35 protrudes a maximum beyond wall 37 because of the above-mentioned eccentricity, flange 35 in interupted with a circumferential recess 39 beneath which wall 37 is chamfered as at 40 in FIGURE 7, this being the area which is grazed by needle 4 during its reciprocating movements).

Recess 39 is defined by loop limiting shoulder 41 and loop holding shoulder 42, each at an opposite end of said recess. Wall 37, contrary to conventional hook assemblies, is closed at its bottom end by bottom wall 43 and is open only at its upper end. Extending radially outward from the upper end of wall 37 and parallel to flange 35 is rigid projection 44 which includes a recess 48 directly above recess 39. Projection 44 and shoulder 41 are connected together by means of substantially conical surface 45 on which runs the thread coming from the needle so as to wind the bobbin holder. The bobbin holder wall 37 includes beneath projection 44 with a circumferential portion on which is mounted resilient element 47 whose purpose is to tension the thread.

The purpose of recess 48 is to engage or embrace a fixed fastening means on the machine housing, such as plate 49 which secured by screws 50 to either the base housing 1 or to the needle plate 2. Such engagement is made possible by the inclined disposition of the hook assembly which prevents the bobbin holder 36 from falling away from hook gate body 23 whereby said holder 36 may be accurately positioned in place before the gate cover 51 is closed. Contrarily, in prior known types of hook gates, the fastening means for the bobbin holder (analogous to plate 49 herein) is fixed to the gate cover whereby the exact positioning of the bobbin holder is finalized only after the cover is closed.

Gate cover 51 (FIGURES 1 and 5) is formed from two plates 52 and 53 between which a soft-material, elastic ring 54 is held, the plates being held together by folding over tongues 55 on plate 52. Guide pin 56 extends axially from the top of plate 53.

If the sewing machine is a free arm type machine, pin 56 is fixed by means of screw 57 to a projection 58 on housing cover 59 which closes the front portion of the machine base housing 1. Housing cover 59 is hinged to the stationary portion 61 of housing 1 by means of fixed pivot pin which is parallel to shaft 11. A latch 64 acts in conjunction with pin to hold housing cover 59 in closed position and this in turn serves to hold gate cover 51 in closed position.

If the sewing machine is a flat base type machine (FIG- URE 3) pin 56 is fixed to a projection 62 of a sliding plate 63 which closes the base housing front part up to the needle plate 2. When plate 63 is slid to its open position (towards the right) the gate cover 51 moves with it, but bobbin holder 36 remains in place, with recess 48 engaging fastening plate 49.

Because the hook axis is inclined, the bobbin holder 36 can be easily removed from hook gate body 23, and since the bobbin holder 36 is closed by bottom wall 43, the bobbin 38 cannot itself fall away from the holder 36 as said holder is being removed from the body 23.

The removal of the holder 36 is possible regardless of the position of the needle 4, since said needle engages the body 23 behind the holder 36.

What is applicable to removal of the holder 36, is obviously also applicable to insertion of this member.

Because of the particular position of the hook and its shape, the thread tensioning means 47 can be adjusted without removing the holder 36 from hook body 23.

It is to be understood that the above relates to only a preferred embodiment of the invention and that all other embodiments thereof and obvious modifications are intended to come within the scope of the appended claims.

What is claimed is:

1. A sewing machine comprising a hook assembly for the lower thread of said sewing machine, said assembly comprising a rotatable hook gate body shaft whose axis is inclined at an angle of 35 to 55 degrees to the horizontal, a hook gate body rigidly mounted coaxially with said shaft, a bobbin holder removably mounted within said hook gate body, fastening means securing said bobbin holder against rotational movement, drive means for rotating said shaft, a sewing needle in cooperative alignment with said hook gate body, said shaft being linearly displaceable along its rotative axis and angularly displaceable about an axis perpendicular to said rotative axis, and means to adjustably vary the angular and axial disposition of said shaft whereby the alignment between said hook gate body and said needle is variable.

2. The sewing machine of claim 1, including a bearing member which rotatively supports said shaft, said bearing member being adjustably rotatable between fixed positions about an axis which is perpendicular to the rotative axis of said shaft whereby rotary displacement of said bearing member changes the angular disposition of said shaft rotative axis and consequently changes the angular disposition of said hook gate body relative to said needle.

3. The sewing machine of claim 2, wherein said drive means comprises a drive shaft extending perpendicularly to the rotative axis of said hook gate body shaft and cooperating bevel gears mounted respectively on said body shaft and on said drive shaft, said bearing member comprising an elongate bushing coaxially surrounding said body shaft.

4. The sewing machine of claim 3, wherein said elongate bushing is mounted in a body member which is rotatably mounted in a fixed housing portion of the machine, said bushing extending perpendicularly to the rotary axis of said body member, first adjustment means to secure said body member in any one of a plurality of fixed rotary positions relative to said housing portion.

5. The sewing machine of claim 4, said elongate bushing being linearly displaceable relative to said body member in a direction perpendicular to the rotary axis of said body member, said body shaft being axially fixed relative to said elongate bushing, second adjustment means to secure said bushing in any one of a plurality of fixed positions in a linear direction perpendicular to the rotary axis of said body member.

6. The sewing machine of claim 4, wherein the rotary axis of said body member is coaxial with the rotary axis of said drive shaft, said body member being disposed endto-end with said drive shaft.

7. The sewing machine of claim 1, said hook gate body comprising a gripping point rotatable along a circular trajectory about the axis of said body shaft and thread guide plate radially exterior of said point and overlapping substantially the entire upper axial surface of said point, said guide plate including a tongue which extends radially inward slightly past the radial position of said point and axially adjacent to said point, said needle being reciprocable in cooperative alignment with said point, the axis of said need-1e being radially displaced inward of the circular trajectory of said point, said tongue serving to prevent said needle from extending into said circular trajectory.

8. The sewing machine of claim 7, said hook gate body comprising a circular rim which is circumferentially interrupted by a recess, said point being constituted by one end of said rim which defines one of said recess, said guide plate being curved in accordance with the curvature of said rim and being mounted on the exterior surface of said rim and bridging said recess.

9. The sewing machine of claim 1, including a bushing coaxial with said body shaft, said body shaft being rotatably mounted in said coaxial bushing, said bushing being mounted on an adjustably pivotable member whose ivot axis is perpendicular to the rotational axis of said body shaft, said bushing being adjustably axially shiftable relative to said pivotable member.

References Cited UNITED STATES PATENTS 251,517 12/1881 Bruncker 112191 266,977 11/1882 Darling 112 191 2,148,385 2/1939 Waterman 112184 2,623,486 12/ 19.52 Scheiwiller 11225 8 X 3,031,989 5/1962 Engel et a1. 112-186 X 3,120,204 2/ 1964 Ketterer 112228 FOREIGN PATENTS 37,472 11/ 1886 Germany.

HERBERT F. ROSS, Primary Examiner. 

